A multi-disciplinary approach is proposed in this Program Project to define and characterize the basis by which the synapsin family of phosphoproteins promote synaptogenesis and stabilize synapses. A greater understanding of the molecular mechanisms which are responsible for these effects should lead to novel therapeutic targets for the treatment of Alzheimer's disease. A wide range of studies will be performed at distinct levels of organizational complexity to define the trophic properties of synapsins, encompassing in vitro biochemical studies with purified molecules, cellular systems that accommodate experimental manipulation, and morphological and behavioral studies in intact animals, analyzing the phenotypic changes that can be observed as a consequence of the targeted deletion of one or both of the synapsins genes in mice. The Scientific Core is designed to provide a range of technical support services to the other members of the Program Project. The responsibilities of the Scientific Core will include the production and supply of key reagents and the performance of routine, yet essential tasks that will be required to accomplish the studies described in research Projects of the application. The centralized organization of support functions will facilitate a reliable, efficient, and cost-effective means to ensure an adequate supply of materials. The Core staff will maintain the colonies of synapsin I, synapsin II, and synapsin I/II "double" knock-out mice and perform genotyping of offspring. Animals will be bred to provide the required number of animals for study in Projects I, II and IV, and regular delivery of timed-pregnant females will be provided to support the culture facility (Specific Aim 1). The Core will maintain a tissue culture facility to provide a continuous supply of cultured mouse embryonic hippocampal neurons to Projects I and II (Specific Aim 2). The Core will be responsible for the production and screening of polyclonal antibodies that are required for Projects II and III, including domain-specific and species-selective antibodies to Xenopus synapsin I and II isoform, and phosphorylation state-specific antibodies for MAP kinase-dependent sites on mammalian synapsin II and Xenopus synapsins I and II (Specific Aim 3).